Emigrated as a child to Rotterdam. 1947 return to Vienna. 1950-68 state worker at the national bank. Shortly afterwards connected with Strohkoffer and Art-Club, the artistic groups of that time. Since 1952 experimental 8mm films, also in collaboration with Konrad Bayer; these films however have been lost. Close contact to Marc Adrian and Pahdi Frieberger, later also with the Op-Art artist Helga Philipp. Since 1957, 16mm works with a serial montage technique, which belong to Kren's major pieces. Due to these Kren is considered a leading advocate of structural film along with Peter Kubelka, who arranged Kren's first film presentation in 1961 at the Viennese gallery, Nächst St. Stephan. 1964-65 films of Otto Mühl's and Günter Brus' "material actions." 1966 participation in the Destruction in Art Symposium in London, where the Viennese actionists made their first appearance abroad. 1968 first trip to America with film presentations in New York and St. Louis. In the same year, participation in the event Art and Revolution at the University of Vienna where his films were confiscated by the police and as a result of which he was fired from his position at the bank. 1971-76 lived in Cologne, where he began the production of his "Boxes," and initiated the project Kunst bleibt Kunst (Art remains Art). His work is now shown by the London and New York Filmmakers' Cooperative as well as P.A.P. (Progressive Art Productions) in Munich. Since 1977 numerous exhibitions. 1978-89 lived in America. Married Marnie Rogers and returned to Europe in 1979 for a short period on a DAAD scholarship. In 1980 divorced and moved to California living without permanent address, sometimes just in his car. 1981 worked as a wrecker of wood houses in New England making money from the wood he salvaged. Later moved to Austin, and then on to Houston, Texas. There the punk band Really Red raised 1000 Dollars for Kren at a benefit concert. From 1983-89 worked as security guard at the Museum of Fine Arts in Houston. Numerous film presentations in different cities and purchases of his works for international collections. 1989 return to Austria. Co-founder of the Vienna Institute of Direct Art (1966) and of the Austria Filmmakers Cooperative (1968). Member of the Viennese Secession, the London Filmmakers' Coop (1967), the New York Filmmakers' Coop (1968), P.A.P. Munich (1968) and of Assembly of Authors in Graz.
